Puerto Rico is an island between the Caribbean Sea and the North Atlantic Ocean, located east of the Dominican Republic. The island is almost rectangular in shape and is the smallest and most eastern island of the Greater Antilles. The island spans an area of 9,104 sq. km, slightly less than three times the size of Rhode Island. The island has a length of 180 km, stretching from Punta Puerca in the east to Punta Higuero in the west. The maximum width spans an area of 65 km from Isabella in the north to Punta Colon in the south. The length of the coastline is 501 km, which is the reason for Puerto Rico being a key -shipping lane to the Panama Canal. In addition to the principal island, the Commonwealth includes Vieques, Culebra, Culebrita, Palomino (also known as the Spanish Virgin Islands), Mona, Monito and various others isolated islands.

To the west of the island lie Haiti and the Dominican Republic, which are separated from the island by the Mona Passage or Mona Canal. To the east lie the Virgin Islands. The north is flanked by the Atlantic Ocean while the Caribbean Sea is to the south.

Puerto Rico has a predominantly mountainous terrain. The coastal plains are spread across the north of the island. Sandy beaches cover the coastal areas. Cerro de Punta is the highest point at a height of 1,338m. San Juan is one of the biggest natural harbors.

Puerto Rico’s numerous small rivers and high central mountains ensure that the land is well watered. The south coast is relatively dry and the north consists of a fertile coastal belt.

Puerto Rico is close to the deepest submarine depression in the North Atlantic Ocean. The Puerto Rico Trench is about 1,750 km long and 100 km wide. The trench was formed by a series of faults in the north Caribbean and is partially filled with sediments. The trench is parallel to the northern coast of the island of Puerto Rico, lying about 120 km to the north. The deepest point in the Atlantic Ocean, the Milwaukee Depth, lies within the Puerto Rico Trench, at a depth of 8,380 meters, 160 km northwest of Puerto Rico.